function mascara(e,src,mask) {
	if(window.event) {
		_TXT = e.keyCode;
	}
	else if(e.which) {
		_TXT = e.which;
	}
	if(_TXT > 47 && _TXT < 58) {
		var i = src.value.length;
		var saida = mask.substring(0,1);
		var texto = mask.substring(i)
		 if (texto.substring(0,1) != saida) {
			src.value += texto.substring(0,1);
		}
		return true;
	} else {
		if (_TXT != 8) {
			return false;
		} else {
			return true;
		}
	}
}